'All I need to do is dive into another dimension, find the time traveller, help her escape the monster, bring her home before the dimension collapses and Bob's yer uncle!'

Doctor Who does a haunted house. Now where have we heard that one before? This is potentially treacherous ground, since last time they did something similar they came up with one of the most beloved episodes ever, in Blink. Even that title echoes it.

But Neil Cross's spooky story has enough going on of its own to set it well apart, and the upshot is the second cracker in a row. The sepia-tinted 1970s, all blouses, polygraphs and Edinburgh-crystal whisky glasses, makes for an atmospheric awayday in this crooked pile. Despite all that, The Witch of the Well turns out to have a proper sci-fi explanation behind her (complete with a now-obligatory element to the story of love saving the day). The danger itself, like the story, is not huge: a human mystery in need of resolution rather than a high-stakes, Earth-threatening standoff, but its tension was just right for such a small-scale, contained and atmospheric tale. With another week comes more impressive guest stars, Dougray Scott casts a noble shadow as Professor Alec Palmer, a war hero turned ghosthunter and Jessica Raine is charming as psychic Emma Grayling, the "non-objective equipment". They're both haunted by death in different ways, and together they form a melancholic mirror to the Doctor and Clara themselves; a worrying portent to the way things could go for these two. There's even a neat in-joke about whether the women are "companions" or "assistants" (this is still the 70s). It's a seamless exercise in demonstrating how less can be more; Hide has the hallmarks of an episode that will be discussed for years to come.

'Every lonely monster needs a companion'

I'm loving the storyline about the Tardis bullying Clara. The ship seems to think the new companion is a right piece of work, something that will no doubt pay off in next week's story, Journey to the Centre of the Tardis. This, though, was the first episode Jenna-Louise filmed, and it shows a little: she's not completely there yet with the character or the relationship. It can never be easy writing a companion you've never seen on screen, but lines such as: "I dispute that assertion," and, "Whisky is the eleventh worst ever invented," don't sound quite like the sort of things anyone would actually say. Actually the whole script felt a bit too writerly and the dialogue jarred a touch – as if the writer was showing off a bit but it doesn't quite ring true. See also: "There's a sliver of ice in his heart."

Fear factor

Yes, this worked most of all because it was properly chilling, not just in the candlelit corridors of Caliburn House, but in the forests of the sub-universe. When the Doctor declares "I am scared", he might be chiding the monster, but it sounds convincing.

Director Jamie Payne, a newcomer to the show, handles the scares deftly, with an old-fashioned it's-behind-you! approach to ramping up the tension. And in a show where even the scariest monsters can have a tendency for the cute, here was one that made you take a good few steps back to toward the back of the sofa with every glimpse. Fantastic.

Mysteries and questions

The twist at the end is that the Doctor has lied to Clara about their visit to Dorset; his increasing obsession with her led him there to see whether Emma the Empath could shed any light on the mystery of the impossible girl. But she can't offer anything more substantial than that she's real, normal and more scared than she lets on. Still, for the Doctor she's now "the only mystery worth solving". And while the reality of time travel would be difficult for anyone to get their heads round, Clara herself is starting to twig that everything's not quite as it should be. "Not everything ends," says Emma. "Not love, not always." Is that the clue to it all? That love has the power to fracture somebody across time? It would be on message.

Meanwhile the Doctor has been darkening for some time now. It's the arc as actors move towards the end of their tenure in the role. But Emma fears that Clara should not trust him – so is she sensing something to do with his Greatest Secret we're being teased with? What do you think it could be?

Time-space debris

• Probably for the first time in the show's history, Cross was actually asked to go away and spend more money on his claustrophobic script – which probably accounts for the slightly extraneous spacesuit scenes.

• I wasn't feeling the Ghostbusters reference too much, mostly because it brought back unpleasant memories of this:

• Expect the mayor of Carlisle to be writing a strongly worded letter to the BBC first thing Monday.

• The Tardis is like a cat, says the Doctor, slow to trust. YES. This is why I have never been a dog person: it takes longer to get a cat to trust you, but when you get there you've got a friend for life.

• "Doctor What?" "If you like."

• Health and safety wasn't quite the thing in 1974 that it is now. The Doctor didn't even bother faking his credentials to Alec and Emma with the psychic paper.

Next week

We're off on an epic Journey to the Centre of the Tardis. Writer Steve Thompson birthed a dud with last series' pirates debacle, but nobody should underestimate the man who wrote last year's Sherlock finale …